In lg skillet, saute onion and garlic in butter for 4 min or until crisp-tender. Stir in flour, pepper and salt until blended. Gradually stir in milk. Bring to boil, cook, stir for 2 min or until thickened. Stir in 1 cup of cheese. Reduce heat, cook for 2 min or until cheese is melted. Remove from heat; gently stir in the potatoes, ham and broccoli.